Valved bag



2 Sheets-Sheet 1 M. BATOSTI ETAL VALVED BAG lnruinnaxuiz. q llllllll 1-llll I: i v: 3.5.1..- ..ln- 5.1.235:

Aug. 17, 1965 Filed June '7, 1963 MARIO BATOST I ANTONIO BELLONI g- 1965M. BATOSTI ETAL VALVED BAG 2 Sheets-Sheet 2 Filed June '7, 1963INVENTORS BATO 6T1 ANTONIO BELLON l MARIO ATTORNEY United States Patent3,201,023 VALVED BAG Mario Batosti, Milan, and Antonio helical, Padova,ltaiy, assignors, by mesne assignments, to Edison, Milan, Italy, acorporation of ltaiy Filed June 7, H63, Ser. No. 286,387 4 Ciaims. (tCl.229-625) This invention relates to a valved bag and method of formingsame, having squared off, sealed ends, in at least one of which there isformed a tubular valve of the type which closes automatically as aresult of the thrust exerted by the material with which the bag isfilled. More precisely, this invention relates to a bag manufactured ofa plastic material having a substantially square shape which is capableof offering excellent mechanical resistence and reliable stability in anupright position when filled.

At present, bags of synthetic material with or without valves, areclosed at the two ends by welding of the tubular envelope forming thebag, so that, when filled, they have difficulty in remaining upright andsteady; on the other hand, those bags having glued-on bottoms or thelike, i.e. bottoms which are distinct from the tubular envelope andwhich are generally closed by glueing the bottoms thereon, have littlemechanical strength at the glued portions.

An object of this invention is to provide a bag with squared off endsand a method of preparing the same such that the filled bag will have aparallelepiped-like shape and will have excellent stability andsturdiness.

Another object of the invention is to provide a simple and practicalmethod of preparing a valve bag manufactured of a synthetic plasticmaterial, which valve provides a secure seal even when the bag is filledwith powdery or generally incoherent material.

Still another object is the provision of a valved bag and method whichis particularly suitable for continuous machine production at relativelylow cost with a minimum of waste.

These and other objects and advantages will be readily appreciated fromthe following description.

In accordance with this invention our novel valved bags having asubstantially squared off shape may be manufactured from a flattenedtubular piece of synthetic material or ffom a sheet of same which can beformed into a tubular configuration. The valved bags of this inventionare characterized by substantially squared off fiat rectangular ends.Where sheet material is used initially, the opposite sides are joined,for example, by welding to form tubes of the material. The corners arethen closed by sealing means running at 90 angles to the aforesaidjointure. A tubular valve is formed in one of said closed ends, whichvalve is defined laterally by overlapping areas of the bag sides and bythe transverse joining of said areas, communicating with the inside ofthe bag by a slit formed in the innermost sideof said overlapping endswhich form the ends of the bags.

The invention will now be described in greater detail according to apreferred but not exclusive embodiment thereof, with reference to theaccompanying sheet of drawings which illustrate without limiting theinvention and in which:

FIG. 1 shows in a perspective view a starting portion of tubular plasticwith open ends, and illustrates the starting stage for the manufactureof a valved bag according to the invention;

FIG. 2 shows also in a perspective view a second operational stagecomprising the transverse joining of the ends of the tube.

FIG. 3 shows a plan view of a bag with ends finished 3,Z@.l,fi29 liatented Aug. 17, 1965 and with the waste pieces still to be removed, andin which the position is rotated through with respect to FIG. 2;

FIG. 4 shows in a perspective view two extreme portions of the closedends of the bag with the waste pieces still to be removed, but rotatedwith respect to FIG. 3, and in which the tubular valve in accordancewith the present invention is visible in one of said closed ends.

FIG. 5 shows a plan view of a finished bag prepared in accordance withthe method of this invention.

FIG. 6 shows a partial perspective view of the end of the valved bagillustrating the position of the communicating slit;

FIG. 7 represents a perspective view of the valved bag immediately afterclosure of the flaps and illustrates the communication to the inside ofthe bag through the slit; and

FIG. 8 shows a partial perspective view of another operational stage inthe preparation of the valved bag and illustrates the relation of theflaps to the communieating slit immediately prior to closure.

With reference to these figures, the valved bag to which this inventionrelates is formed from a length of plastic tube or from a plastic sheetwhich can be reduced to a tubular form, which is first flattened and theends thereof are then closed by successive folding, overlapping andwelding operations, as will be hereunder described, so as to. formsquared off bottoms, the valve being provided for in at least one ofsaid bottoms.

After the flattening of the tubular piece of plastic material theflattened tube 1 (FIG. 1) is partially cut at the opposite ends alongthe lines of flattening so as to obtain two pairs of free ends viz.,flaps 2, 3 and 4, 5; in flap 5 there is cut a longitudinal slit 5 whichserves, as will be disclosed hereinafter, to put the valve incommunication with the inside of the bag; a piece end of flap 4 iscut-oif so that flap is made shorter than flap 5 in order tobetter'define the valve entrance area. Flaps 2, 3 and 4, 5 are thenfolded inwardly along lines 6, 6 and 7, 7' so as to overlap each otheras indicated in FIGURES 2 and 8 and to form open ended sheath-likeherns.

In doing this, care should be taken that cut-off flap 4 overlapsexternally the cut in flap 5.

The inner flaps are fastened to the outer flaps by means of the pairs ofthe transverse and superposed welds 8, 8' and 9, 9 respectively; saidwelds being carried out in a single stage by introducing into theinterspace formed by the folded inner flaps 3 and 5, insulating memberswhich serve to prevent the welding together of the upper half with thelower half of the inner flap.

During these welding operations, near cut 5 of the flap 5, alongitudinal weld 10 is made in order to join the outer flap 4 to theinner flap 5 in a zone which is situated on the portion opposite to thatwhich will form the valve. In this manner (FIGURES 2 and 3), the valveis in practice defined by the tubular zone formed by cut-off flap 4,flap 5 and delimited by a part of the parallel welds 8, 8 and the weld10. The valve thus communicates with the inside of the bag through slit5' while weld 1t) defines the length of said valve as shown in FIGURES6, 7 and 8.

Once the pairs of welds S, 8' and 9, 9' and weld 119 have beencompleted, the bottoms folded over one another remain open at theirends. To close them, the bottoms and a contiguous zone of thelongitudinal edges of the flattened tube are first spread transverselyto the plane of flattened tube 1 and then the corners of these bottomsincluding the above said contiguous zone are overturned in the directionof the center line of tube 1 by bending them through an angle of 180,whereby the openings of the bottoms are covered by the corner zoneswhich then assume a quadrangular shape. The open covered ends than theunderlying flap 5.

of the bottoms are then closed by means of longitudinal welds ll, 11 and12, 12' by inserting between the triangular zones 13, 13', 13 and 13 andthe bottoms of the bag, isolating sheets so as to avoid welding up thetriangular zones to the bottoms of the bag. With these welds, thetriangular zones 13, 13', 13" and 13" form waste pieces or ears whichare subsequently cut off.

At the valve entrance zone, waste ear 13 has a different shape fromthe'other waste ears, for flap 4 is shorter Waste car 13", therefore,when removed, leaves a free entrance'to the valve as shown by thenumeral 14 in FIGURES 4, 5, 6, 7 and 8. In FIG. 4, for clearness sake,the waste pieces or cars 13, 13 and as Well as 13 and 13" not shown inthe figure, are rotated with respect to FIGURE 3. The actual path ofcommunication with the interior of the bag is shown by the arrows inFIGURES 6, 7 and 8.

With longitudinal welds 11, 11, 12 and 12, which are at an angle of 90to transverse welds ti and 9, the bottoms of the bagassurne a squaredoff shape when the bag is filled, and cause the whole bag to assume aparallelepiped (squared off) shape of excellent stability both when thebag is upright by itself and also when it is stacked away with otherlike bags.

The pair of transverse welds 8 and 9, which join the overlapping flapsmaking up the bottoms at two zones, confer. a mechanical strength on thewhole which is much greater than that obtained by glueing and likesystems, while the valve formed in one of said bottoms enables a perfectseal to be provided for against accidental leakage of materials, evenwhen said materials are finely powdered.

In summary, the method of the invention comprises cutting up a tubularfilm or joining the edges of opposite position to the flap having thelongitudinal slit therein and overlapping the thusly formed flaps insuch a manner that the flap having the longitudinal slip liesinteriorly. The transverse edge of the longitudinally slit flap is thenjoined to the interior of the opposite side of the tube and thetransverse edge of the opposed flap is joined to the exterior of theopposite side of the flattened tube. The same technique of overlappingand joining the free ends on the opposite end of the tube is followedwith these ends. The overlapped ends of the tube are then transvers'elyflattened. 'The open ends are then folded inwardly (as shown in FIG. 4)and the corners joined to form a sealed bottom or top for the bag as thecase may be. It will be appreciated that by utilizing the simple andpractical method of this invention a valve is automatically formed whichmay be readily used for filling and emptying and which also provides asecure seal even when the bag is filled with powdered material. 7

It will also be readily apparent that within the scope of the presentinvention, the tubular valve may be formed in one or both ends of thebag and moreover, more than one valve may be formed in each end. In thelatter case, two longitudinal slits 5 will be effected on the flap at asuitable distance one from the other.

Obviously, in pactice, the materials employed and the dimensions of thevarious constituent parts may vary according to requirements, withoutdeparting from the scope of the invention.

We claim:

'l. A valved bag of synthetic materialrhaving welded ends and asubstantially squared oif shape, comprising; a flattened tube ofsynthetic material partially slit longitudinally along the flattenededges thereof forming a pair of free end flaps on each end of said tube;said free end flaps of the two opposite sides being overlapped andconjoined by means of welds located transverse tothe flattened tube, andclosed on the corners thereof by Welds located at ninety degree anglesto the said transverse welds; a longitudinal slit located in the innerflap of one of said overlapping ends intermediate from the-side there-,

of; a tubular valve formed in the end having said slit;

said valve being laterally defined by the said overlapping claim 1wherein the welds conjoining the overlapping ends are located transverseto the flattened tube edges and.

longitudinal near the communicating slit, said weld adjacent to the slitdefining the length of the tubular valve.

4. A valved plastic bag having welded ends and a substantially squaredoff shape, comprising; a flattened tube of plastic material partiallyslit longitudinally along the flattened edges thereof forming a pair offree endflaps on each end of said tube; said free end flaps of the twoopposite sides of the tube conjoined by means of welds locatedtransverse to the flattened tube and closed on the corners thereof bywelds located at ninety degree anglesv to the said transverse welds; alongitudinal slit located in the inner flap of one'of said overlappingends and intermediate from the side thereof; a tubular valve formed in Vthe end having said slit; said valve being laterally defined by the saidoverlapping ends area of the tube sides and by the said transversewelds, and. communicating with the inside of the tube through said slit.

References Cited by the Examiner FOREIGN PATENTS 178,328 4/54 Austria.474,261 9/52 Italy. 507,225 12/ 5 4 Italy. 974,534 1/ 61 Germany.

FRANKLIN T. GARRETT, Primary Examiner.

1. A VALVED BAG OF SYNTHETIC MATERIAL HAVING WELDED ENDS AND A SUBSTANTIALLY SQUARED OFF SHAPE, COMPRISING; A FLATTENED TUBE OF SYNTHETIC MATERIAL PARTIALLY SLIT LONGITUDINALLY ALONG THE FLATTENED EDGES THEREOF FORMING A PAIR OF FREE END FLAPS ON EACH END OF SAID TUBE; SAID FREE END FLAPS OF THE TWO OPPOSITE SIDES BEING OVERLAPPED AND CONJOINED BY MEANS OF WELDS LOCATED TRANSVERSE TO THE FLATTENED TUBE, AND CLOSED ON THE CORNERS THEREOF BY WELDS LOCATED AT NINETY DEGREE ANGLES TO THE SAID TRANSVERSE WELDS; A LONGITUDINAL SLIT LOCATED IN THE INNER FLAP OF ONE OF SAID OVERLAPPING ENDS INTERMEDIATE FROM THE SIDE THEREOF; A TUBULAR VALVE FORMED IN THE END HAVING SAID SLIT; SAID VALVE BEING LATERALLY DEFINED BY THE SAID OVERLAPPING ENDS AREA OF THE TUBE SIDES AND BY THE SAID TRANSVERSE WELDS, AND COMMUNICATING WITH THE INSIDE OF THE TUBE THROUGH SAID SLIT. 